What distinguishes a human being from a computer? The ability to add up numbers? The ability to understand language? The ability to be logical? It is, of course, none of the above. It is the ability to play. Computers cannot have fun. They cannot fantasize. They cannot dream, they cannot experience emotion or summon intuition. These rare, precious qualities come naturally to every child on this earth yet they tend to be seen, by well meaning adults, as faults, foibles and failings. In pushing tiny toddlers to 'perform', we rob them of the ability to imagine.